版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)
文檔簡(jiǎn)介
PROFESSIONALENGLISHUnit2ConnectingRodsandCrankshaft
Unit2
ConnectingRodsandCrankshaft
Readingmaterial
EngineConditionTests本次課學(xué)習(xí)內(nèi)容本次課學(xué)習(xí)目標(biāo)掌握活塞連桿、曲軸主要部件的英文名稱掌握常用術(shù)語(phrasesandexpressions)了解相關(guān)術(shù)語(relatedterms)
NEWWORDSmechanism[‘mek?niz?m]n機(jī)械assembly[?‘sembli]n裝配crankcase[‘kr??kkeis]n曲軸箱function[‘f??k??n]n功能mechanical[mi‘k?nikl]adj.機(jī)械的vehicle[‘vi:ikl]n車輛cylindrical[si‘lindrikl]n圓柱體;汽缸block[bl?k]n塊;滑輪serial[‘si?ri?l]adj連續(xù)的;一系列的cast[kɑ:st]n,v鑄件;澆鑄suck[s?k]vt.吸intricate[‘intrikit]adj復(fù)雜的rigid[‘rid?id]adj堅(jiān)硬的;剛性的distortion
[dis‘t?:??n]n變形;扭曲inertia[in‘?:?i?]n.慣性;慣量periodic[.pi?ri‘?dik]adj.周期的taper[‘teip?]adj.錐形的diameter[dai‘?mit?]n.直徑groove[ɡru:v]n.溝,槽reciprocating[ri‘sipr?keiti?]adj.往復(fù)的;來回的rotary[‘r?ut?ri]adj.旋轉(zhuǎn)的;轉(zhuǎn)動(dòng)的transmit[tr?nz‘mit]vt.傳送shank[???k]n.軸;柄crank[kr??k]n.曲柄;曲軸bearing[‘b??ri?]n.支承;承受camshaft[‘k?m?ɑ:ft]n.凸輪軸actuate[‘?ktjueit]vt.開動(dòng)(機(jī)械等);驅(qū)使journal[‘d??:nl]n.軸頸excessive[ik‘sesiv]adj.過度的distortion[dis‘t?:??n]n.扭曲;歪曲absorb[?b's?:b]vt.吸收NEWWORDSclutch[kl?t?]n.離合器;聯(lián)軸器turbulence[‘t?:bj?l?ns]n.紊亂circumference[s?‘k?mf?r?ns]n.圓周shallow[‘??l?u]adj.淺的indentation[,inden‘tei??n]n.凹槽indicate[‘indikeit]vt.指示;指出mechanism[‘mek?niz?m]n.機(jī)械;機(jī)械裝置compose[k?m'p?uz]vt.組成;構(gòu)成pistonrings活塞環(huán)connectingrod
連桿pistonpin
活塞銷NEWWORDSAND
PHRASESConnectingRodsandCrankshaft
Inanengine,thepowermechanismiscalledthecrankshaftandconnectingrodassembly.Pistonrodgroupconsistsofpistons,pistonrings,pistonpin,connectingrodetc(seeFig2-1Apistonandaconnecting-rods).Inthisassembly,allofthemajorunitssuchastheenginecrankcaseandcylinderblock,thepistonandconnectingrod,thecrankshaftandflywheelworktogethertoconvertthermalenergyintomechanicalenergyusedtodrivethevehicle.PistonsThepistonconvertsthepotentialenginesofthefuelintothekineticenergythatturnsthecrankshaft.Thepistonisacylindricalshapedhollowpartthatmovesupanddowninsidetheenginescylinder.Duringintakestroke,thepistonsucksthefreshchargeofair-fuelmixturethroughinletvalveandcompressesduringthecompressionstrokeinsidethecylinder.Bythiswaypistonreceivespowerfromtheexpandinggasesafterignitionincylinder,alsoforcestheburntexhaustgasesoutofthecylinderthroughexhaustvalve.
Designerstrytokeeppistonweightlow,particularlyinhighspeedengines.Inordertolightenthepistonistomakeitoflightmetal.Theidealpistonmaterialwouldbelightandstrong,conductheatwell,expandonlyslightwhenheated,resistwear,andbelowincost.Thus,mostenginepistonstodayaremadeofaluminum,whichislessthanhalfasheavyasiron.Ironpistonswerecommonintheearlierengines.Aluminumexpandsmorerapidlythanironwithincreasingtemperature.Pistonscanbedividedintothreeparts,pistoncrown,pistonheadandpistonskirt.Thetoppartofthepistonisthehead,orcrown.Thecrownismachinedonslighttaper,thediameterbeinggreatestwherethecrownmeetstheskirtandbecominglesstowardthetop.Thepistoncrownmaybeflat,concave,domeorrecessed.PistonRings
Pistonringsmustbeusedtoprovidethenecessaryseal.Theringsareinstalledingroovesinthepiston.Actually,therearetwotypesofrings,compressedringsandoil-controlrings.Pistonringspreventsthecompressedchargeoffuel-airmixturefromleakingtotheothersideofthepiston.Oilringsisusedforremovinglubricatingoilfromthecylinderafterlubrication.Thisringpreventstheexcessoiltomixwithcharge.Thenumberpistonringswasreducedtothree,twocompressedringsandoneoil-controlring.Theringshavesplit,sothattheycanbeexpandedandslippedoverthepistonheadandintotherecessedgroovescutinthepiston.Theringsaresomewhatlargerindiameterthantheywillbewheninthecylinder.Then,whentheyareinstalled,theyarecompressedsothatthejointsarenearlyclosed.Compressingtheringsgivethemaninitialtension;theypresstightlyagainstthecylinderwall.1-2-compressionrings3-oilrings4-piston5-pistonpin6-piston-pinring7-connectingrodbushing8-connectingrod9-connectingrodbolt10-connectingrodnut11.12-crankbearinghalfshells13-connectingrodcapCoolingsystemThecombustionoftheair-fuelmixtureintheenginecreatesveryhightemperature.Thecoolingsystemtakesheatawayfromtheenginebycirculatingaliquidcoolant(watermixedwithantifreeze)betweentheengineandaradiator.Thecoolantgetshotasitgoesthroughtheengine.Itcoolsoffasitgoesthroughtheradiator.Thus,thecoolantcontinuallytakesheatawayfromtheengine,whereitcould
do
damage,
and
delivers
theheattotheradiator.Airpassingthroughtheradiatortakesheatawayfromtheradiator.Theroleofcoolingsystemistoabsorbpartoftheheatingparttimelydisseminationoftheheatouttoensurethattheengineattheoptimumtemperatureconditionsatwork.Water-cooledengine'scoolingsystemisusuallysetbythecoolingwater,pump,fans,watertanks,thermostatsoon.Ignitionsystem
Theenginerequiresafourthsystem,theignitionsystem.Theignitionsystemprovideshigh-voltageelectricsparksthatignite,orsetfiretothechargesofair-fuelmixtureintheenginecombustionchambers.Ignitionsystemincludesbattery,generator,distributor,ignitioncoilsandsparkplugssoon.ConnectingRod
Connectingrodchangesthereciprocatingmotionofpistonintorotarymotionatcrankshaft.Bythiswayconnectingrodtransmitsthepowerproducedatpistontocrankshaft.TheconnectingrodshowninFig.3.1isinformofabarwithringshapedheadsatitsend.Theyarecomposedofconnectingrodsmallend,connectingrodshank,connectingrodbigend,connectingrodcap,andconnectingrodbearinghalfshells.
Theconnectingrodisattachedatoneendtoacrankpinonthecrankshaftandattheotherendtoapiston,throughapistonpinorwristpin.Theconnectingrodmustbeverystrongandrigidandalsoaslightaspossible.Theconnectingrodcarriesthepowerthrustsfromthepistontothecrankpin.Atthesametime,therodisineccentricmotion.Tominimizevibrationandbearingloads,therodmustbelightinweight.Tomaintaingoodenginebalance,connectingrodsandcapsarecarefullymatchedinsetsforengines.PistonPin
Thepistonpinholdstogetherthepistonandtheconnectingrod.Thispinfitsintothepistonpinholesandintoaholeinthetopendoftheconnectingrod.Thetopendoftheconnectingrodismuchsmallerthantheendthatfitsonthecrankshaft.Thissmallendfitsinsidethebottomofthepiston.Thepistonpinfitsthroughonesideofthepiston,throughthesmallendoftherod,andthenthroughtheothersideofthepiston.Itholdstherodfirmlyinplaceinthecenterofthepiston.Pinsaremadeofhigh-strenghsteelandhaveahollowcenter.Manypinsarechrome-platedtohelpthemwearbetter.Crankshaft(seeFig2-2crankshaft)Crankshaftreceivesoscillatingmotionfromconnectingrodandgivesarotarymotiontothemainshaft.Italsodrivesthecamshaftwhichactuatethevalvesoftheengine.Thecrankshaftiseitherforgedfromahighqualitysteelorcastinahigh-strongiron.ThecrankshaftshowninFig.3.2isactuallymadeupofvariouspartssuchasmainbearingjournals,rodjournal,crankarmbearing,counter-balancedweightandflywheelend.Thecrankshaftisaone-piececastingorforgingofheattreatedalloysteelofconsiderablemechanicalstrength.Itisusuallymadefromcarbonsteel.Thecrankshaftmustbestrongenoughtotakethedownwardthrustsofthepistonsduringthepowerstrokeswithoutexcessivedistortion.Themainbearingjournalsfitintothecylinderblockandthebigendjournalsalignwiththeconnectingrods.Attherearendofthecrankshaftisattachedtheflywheel.FlywheelTheflywheelisarelativelyheavymetalwheel,whichisfirmlyattachedtothecrankshaft.Theheaviertheflywheelorthelargeritsdiameter,thesmallerwillbethespeedchanges.Itsfunctionistohelptheenginetorunsmoothlybyabsorbingsomeoftheenergyduringthepowerstrokeandreleasingitduringtheotherstrokes.Itfitsontotherearofthecrankshaft.Aswellaskeepingtheenginerotatingbetweenpowerstrokesitalsocarriestheclutch,whichtransmitsthedrivetothetransmission,andhasthestarterringgeararounditscircumference.Thereisonlyoneworkingstrokeinfoursoaflywheelisneededtodrivethecrankshaftduringthetimethattheengineisperformingthenon-powerstroke
溫馨提示
- 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 人人文庫網(wǎng)僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。
最新文檔
- 民族區(qū)域自治制度+教案- 高中政治統(tǒng)編版必修三政治與法治
- 紅隼(2023年山東濰坊中考語文試卷記敘文閱讀題及答案)
- Unit+2+Travelling+Around+單詞考查任務(wù)單 高中英語人教版(2019)必修第一冊(cè)
- 高中閱讀理解高頻詞+清單 高三英語上學(xué)期一輪復(fù)習(xí)專項(xiàng)
- 誠(chéng)信是金主題班會(huì)
- 班干部競(jìng)選領(lǐng)導(dǎo)力展示主題班會(huì)
- 安全知識(shí)小劇場(chǎng)主題班會(huì)
- 醫(yī)院處方權(quán)申請(qǐng)書
- 人力資源業(yè)務(wù)工作報(bào)告
- 特種部隊(duì)野外生存教程
- 英語詞匯學(xué)教程課后答案(張維友編著-華中師范大學(xué)出版社)
- 新生兒血栓的預(yù)防及護(hù)理
- 中國(guó)腦卒中報(bào)告2023
- 如何提升服務(wù)水平
- 醫(yī)院培訓(xùn)課件:《護(hù)理查房(癥瘕)》
- 公路橋梁工程施工安全風(fēng)險(xiǎn)評(píng)估指南
- 譯林版高中英語擴(kuò)展創(chuàng)新學(xué)程一Unit4學(xué)案-雅禮版
- 99D102-1 6~10kV鐵橫擔(dān)架空絕緣線路安裝
- Module1Countrylife復(fù)習(xí)(課件)教科版(廣州)英語六年級(jí)上冊(cè)2
- 《米開朗基羅》課件
- 河南周口沈丘縣2023-2024學(xué)年高一上學(xué)期期中英語質(zhì)量檢測(cè)模擬試題(含解析)
評(píng)論
0/150
提交評(píng)論